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Author Topic: Scannerless Digital Capture  (Read 5527 times)

Jim Kasson

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Re: Scannerless Digital Capture
« Reply #20 on: March 22, 2017, 03:56:18 PM »

Thanks for the tips and the additional writeup.

I understand your notion you get better results by bringing all three histograms into the middle range, based on "things are more linear in this range."

My thinking is this: Recent mini-labs were digital, and the vendors had their machines calibrated to the different color negative films. The calibration produced pretty good color most of the time, some tweaks by operators, and the operators weren't master print makers. I wish we had some calibrations (color temp of light source, CC correction at "scan," color profiles, and post-processing parameters) that would give us the same color quality we had from mini-labs.

In the 90s, there was some pretty good hardware and software for color negative scanning. These days, what with the market size being minuscule, not no much. It strikes me that the CFA spectral response that's optimal for the real world is not optimal for teasing out the densities of the three dye layers of color negative film. I would think that using three exposures with different narrow-band illuminants tuned to the center wavelengths of the three dye layers would be better, although it would take a lot of experimentation to sort it all out. If you don't use a monochromatic sensor, you could equalize all of the CFA sites, rather than demosaicing.

Jim

trshaner

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Re: Scannerless Digital Capture
« Reply #21 on: March 22, 2017, 06:07:01 PM »

I get good results using Lightroom to convert the color negative camera raw file and then output to TIFF file for final processing in PS. I've created a PS Action that speeds the processing and an Excel document with settings for 12 different color negative film types. One of the problems with color negative film is color shift due to aging. The PS Action allows correcting color shifts using an RGB curves adjustment layer. It takes some practice, but the article PDF instructions and Excel spreadsheet should help. Using this LR>PS workflow I am able to quickly get good results with even 50 year old Kodak Kodacolor X negatives.

The article PDF here:
https://luminous-landscape.com/articleImages/CameraScanning.pdf

Todd’s Photoshop Action here:

https://www.dropbox.com/s/ffwl30byvbad6kz/Color%20Negative%20Processing.atn?dl=0

Instructions for installing it here:

https://www.dropbox.com/s/zssvl02l29jpiiq/Photoshop%20Actions%20for%20Color%20Negative%20Processing.pdf?dl=0

Lightroom & Photoshop Settings for Color Negative Film Types:

https://www.dropbox.com/s/bgjhi5gabulkuwd/Color%20Negative%20Film%20Workflow%20Settings.xlsx?dl=0
« Last Edit: March 22, 2017, 06:19:10 PM by trshaner »
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Ernst Dinkla

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Re: Scannerless Digital Capture
« Reply #22 on: March 28, 2017, 04:42:57 AM »

In the 90s, there was some pretty good hardware and software for color negative scanning. These days, what with the market size being minuscule, not no much. It strikes me that the CFA spectral response that's optimal for the real world is not optimal for teasing out the densities of the three dye layers of color negative film. I would think that using three exposures with different narrow-band illuminants tuned to the center wavelengths of the three dye layers would be better, although it would take a lot of experimentation to sort it all out. If you don't use a monochromatic sensor, you could equalize all of the CFA sites, rather than demosaicing.

Jim

The real world sensitivity of color negative films is not represented in the dye densities of the developed films. The last are aimed at the sensitivity of the chromogene color papers. Some months ago I converted a Philips PCS2000 color enlarger head to a slide/color - B&W negative copier with a 5D II camera + Sigma 50mm 2.8 macro lens attached. As the halogen lamps were gone and quite expensive to replace I bought some MR11 RGB LED lamps + a 3 channel LED dimmer. The spectral output fits the sensor quite well and the R and B hit the dye densities in an acceptable way but the Green LED at 525 NM peak should be wider, at least towards 540-550 NM, the Blues in the positive image shift too much as the yellow dye density is not hit well this way. Green LEDs are already less efficient than other LED colors but at 540NM the efficiency loss is the deepest in what is called "The Green Gap" in the LED industry.  There are some developments (Lumileds for example) that should change that in time. Meanwhile I aim to bridge that spectral part with a white LED + a broader green camera filter. Another solution is a mix of an Amber and Green LEDs. Ideally the deviation between the peak film dye density at 540NM and the peak sensor sensitivity at 525NM should be compensated by a kind of fluorescence filter between film and sensor, all other narrow LED or (broad or narrow) green filters solutions are a compromise.

For B&W negatives I can replace the RGB LEDs with three 525NM Green LEDs. So far I only use one and the RB LEDs are not used in B&W copying. I wonder whether there would be a gain by using more of the Bayer sensor as discussed in this thread, the more that the lens should be optimal for green light and focusing on the sensor is done with green light only.

The Canon RAWs of the negatives are converted to positive "RAW" Tiffs in Vuescan and imported in ACR. That makes the ACR tools more usable than starting from negative RAWS. In practice the workflow of the color negative copies with more Vuescan involvement worked faster than a more "RAW" approach, image quality similar. For B&W the magenta images (Green LEDs) were only reversed in Vuescan. Grain (aliased without doubt) is sharp. I think that the B&W copies are at the level I could get with my Nikon 8000 scanner, but this goes faster. Wet mounting could be a next step for image quality, another camera too. Lens is good at this 1:1 magnification.

I still have to go the slide route, so far I modified the film holder of the Philips enlarger and that means film strips only. There exist boards for slides for that holder AFAIK but I envision a faster custom slide holder. Contemplated auto focus with the lens at fixed distance (filter thread support) and the camera moving (spring balanced for weight compensation) but for film strips the film plane deviation is not worth it, might change for a diversity of slide mounts though.

 
Met vriendelijke groet, Ernst

http://www.pigment-print.com/spectralplots/spectrumviz_1.htm
March 2017 update, 750+ inkjet media white spectral plots
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Jim Pascoe

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Re: Scannerless Digital Capture
« Reply #23 on: March 29, 2017, 09:51:23 AM »

I have only just seen this topic and of course it originated some time ago.  I have read the link to the methods of capture with a camera and within an hour I have had a go.  I did not spend much time on setting up so this was a 'quick and dirty' trial to see if the method would work for me.

I shot film on both 35mm and rollfilm for many years before going entirely digital in 2003.  I do have an older Epson scanner (a P3200 I think) but the drivers are now out of date and anyway it seemed to take ages to scan.

Today I set up my Canon 5DSr with a 100mm Canon macro lens on a Gitzo tripod.  Got it roughly level pointing straight down.  I have a very old (18 years) Cabin LED lightbox and laid my negs right on top of that.  I stopped the lens down to f8, ISO 200 and fired away without cable release or mirror-up. After importing into Lightroom, I then exported the file into Photoshop, Image - Adjust - Invert to get the negatives into positives.  I adjusted the levels in PS and then saved and back into LR.  Here I adjusted contrast etc, and for the colour pictures just used the WB tool to get the colours approximately right.

I realise that I will need to spend much more time to refine this, and will read the notes linked in this thread again to improve my technique.  But it certainly seems to solve my problem with scanning and the files from the Canon of course are plenty big enough for any use I have.  My pictures on film are not for any commercial use and so I do not need the finest quality anyway - it will be a trade-off between the time I spend on scanning and the end-use of my pictures. 

There are some very clever people on this forum and indeed in this thread.  I'm not one of them and get lost very quickly in technical issues.  I rarely even use layers in PS - in fact 99% of my work is done in LR.  I'm just a photographer who wants simple solutions, and although this technique can be highly refined - for me I want to keep it as simple as possible

A couple of examples attached, both taken around 25 years ago on a Bronica 645.  Yes I know, a manual-focus MF camera is not ideal for action photography.........

Jim
« Last Edit: March 29, 2017, 09:55:43 AM by Jim Pascoe »
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trshaner

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Re: Scannerless Digital Capture
« Reply #24 on: March 29, 2017, 12:04:19 PM »

You can download the documents in my reply #21 and a PS Action, which greatly simplifies color negative processing. In addition I have created an addendum with further refinements to LR's settings as outlined below. This is key to insuring the RGB film image data remains linear during the raw file conversion inside LR or ACR. Let me know if you have any questions. ;)

The PV 2012 Basic panel controls are image adaptive and apply Highlight compression and Black Point setting with all controls at their 0 default setting. What I found works best is to use the WB tool in LR or ACR to reduce the dynamic range of the raw film scan. The objective is to place all three RGB channels into the linear mid-tone region to prevent compression of the highlight and shadow area image data. You can download an addendum PDF with more details here:

https://www.dropbox.com/s/6j3emoq40kqkymb/Color%20Negative%20Camera%20Raw%20Image%20Processing%20In%20Lightroom%20%26%20Photoshop.pdf?dl=0
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Jim Pascoe

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Re: Scannerless Digital Capture
« Reply #25 on: March 30, 2017, 05:17:23 AM »

Many thanks - as soon as I get a moment I will have a look.

Jim
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